INTRODUCTION OF INTERNET

INTRODUCTION OF INTERNET

ORIGIN

The Internet sometimes simply called the Net is a global network of interconnected computers, enabling users to share information along multiple channels. Typically, a computer that connects to the Internet can access information from a vast array of available servers and other computers by moving information from them to the computer's local memory. The same connection allows that computer to send information to various servers available on the network.

It was conceived by the Advanced Research Projects Agency (ARPA) of the U.S. government in 1969 and was first known as the ARPANET. The original aim was to create a network that would allow users of a research computer at one university to be able to "talk to" research computers at other universities. A side benefit of Arpanet’s design was that, because messages could be routed or rerouted in more than one direction, the network could continue to function even if parts of it were destroyed in the event of a military attack or other disaster. We can divide the history of the Internet (till the present) into three main parts.

• FTP: The first stage

• Gopher: The second stage

• The World Wide Web: The third stage

Today, the Internet is a public, cooperative, and self-sustaining facility accessible to hundreds of millions of people worldwide. Physically, the Internet uses a portion of the total resources of the currently existing public telecommunication networks. Technically, what distinguishes the Internet is its use of a set of protocols called TCP/IP (for Transmission Control Protocol/Internet Protocol).

USES

1. Social networking

2. E mail

3. Instant messaging

4. VoIP

5. Information search

6. Downloading

7. News and update

8. Business and shopping

9. Entertainment

10. Gaming

11. Online trading

12. Blogging(web log)

13. Banking application

14. Remote assistance

15. E travelling

16. Education

17. Simulation

18. Real time collaboration and conferencing

How data transfer takes place on the net

Once when we start the browser (a client program) on computer and request for some information, say an HTML file, located on a remote computer. There are two important ways in which information is requested from a browser, a hyperlink is clicked or a URL is entered in the "Address" or "Location" field.

The event can also be generated from the instructions in a program. Thus, we can automate uploading and downloading of files (data transfer) with the help of a program. Let us suppose we requested for an HTML document from a remote computer using a web browser. The browser searches for the remote computer and on locating it, passes the request to a program called the server running on some distant computer. The server then checks up our request and tries to locate the HTML file on its hard disk. On finding it, the server sends this file to our computer.

If this HTML document has embedded image, video, and/or sound files, the information and the content of such files are also passed to the browser. On receiving data from the server, the client which is a browser in our case, starts to display the HTML page. The client holds the sole prerogative ondocument display, with no involvement from the servers' side. Once it sends the data to the remote computer, the server, so to say, washes its hands off it. On receipt of all requested data, the client-server connection is lost. Thus, the next time this client asks for some information from the server, the server will treat it as a new request without any recollection of previous requests. This means that client-server interaction is "connectionless" with every new request generating a new response.

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